Author: Digby Cook

“The question is not if we will regenerate hair cells in humans, but when” – Peter Barr-Gillespie

Dr. Barr-Gillespie & The HRP Team (Jane G. Photography)

That is the mission, and the hope, offered by the Hearing Restoration Project (HRP). This remarkable collaborative effort by a consortium of researchers has been pioneering groundbreaking research since 2011. How close are they to that goal?

First, a little background. For most of us the culprit is sensorineural hearing loss caused by lost or damaged hair cells in our inner ears. Simply put, hair cells are the tiny clusters of sound detectors in our cochleas that are killed by exposure to loud noise, or die off as we age, never to be replaced.

“It’s fair to say most hearing loss is due to some sort of damage to the hair cells or their connections to the auditory nerve,” says Peter Barr-Gillespie, Director of the HRP, “that’s been the focus of HRP and many people in the field. It’s a tough nut to crack.”

HRP researchers scattered across North America are trying to crack that nut by studying two animals that are able to naturally regenerate lost hair cells. Chickens and zebra fish can perform that trick but mammals like us cannot. That riddle is the focus of their research.

(The research consortium includes Prof. Stefan Heller at Stanford whom I interviewed here and Prof. Alain Dabdoub at the Sunnybrook Research Institute in Toronto. I interviewed him here.)

To find the answer they are also studying the cochleas of mice. It seems that mice are pretty good stand-ins for humans.

“Mice are high frequency specialists,” says Barr-Gillespie, and it’s those high frequencies that humans tend to lose. “If there is a therapy that works for a mouse it’s likely that we could take that and use it for humans.”

So what would a treatment for humans look like?

“There are a couple of possibilities, he says. “One, some sort of gene delivery where we would identify the gene that can overcome the blocks to regeneration.”

“But what I would prefer to see is some sort of drug that you could either take by mouth or apply through the ear. The first step we are interested in is finding the right targets and then developing the drug. That would likely involve a pharmaceutical company because they have the resources.”

The big question is, of course, when will any therapy be available? Barr-Gillespie like many researchers in the field talks in terms of five to ten years. But he adds that, “We could be surprised”.

After all science and serendipity often go hand in hand. Back in 1928 a stray fleck of mold came in through an open window in Alexander Fleming’s laboratory, landed in his petri dish and killed the bacteria in it. The result was penicillin.

“From where I sit,” he concludes, “my fingers are always crossed.”

Mine too.

The Hearing Restoration Project is supported by the Hearing Health Foundation which is the largest non-profit funder of hearing research in the United States. I urge you to visit their web site to learn more, and support their work.

Hearing aids help, and I couldn’t function without them. But for those of us afflicted by sensorineural (age related) hearing loss there is now the tantalizing possibility of a cure on the horizon.

Researchers around the world are working on it. I’ve talked with several, and the main focus of their attention are the hair cells and their supporting cells which line the cochlea.

They transform the vibrations produced by sound into electrical signals that are transmitted to the brain. But as we age they die off. They are killed by loud noises, certain drugs and faulty genes. The holy grail in this quest is to find a way to bring them back to life.

Dr. Jeffery Harris

One of those scientists leading the charge is Dr. Jeffery Harris. He is Chief of the Division of Otolaryngology-Head & Neck Surgery at the University of California, San Diego. Not only is he a renowned surgeon but he also leads a team of researchers who are studying the causes of deafness.

In this new video, Dr. Harris gives a clear and concise explanation of the current state of the research and offers more than a glimmer of hope:

Odd but intriguing research is underway at Colorado State University. Engineers are developing a mouth piece that can transmit the sensation of sounds to the tongue.

As anyone who has savoured a fine meal knows, the tongue is rich with sensory nerve cells. What if those cells could also be used transmit sound, or at least an interpretation of sound, to the brain bypassing the ears completely?

That’s concept the CSU researchers are working on and they produced this video to show how it might work.

A German observation post, 1917. The ear horns were used to detect the sound of incoming enemy aircraft and to help spot them, the goggles acted like binoculars.

Canadian Prime Minister Justin Trudeau led commemorative services this week to mark the 100th anniversary of The Battle of Vimy Ridge in World War 1.

Vimy Ridge has come to symbolize Canada’s coming of age. For the first time Canadians from all across the country fought together under Canadian command. Their decisive victory over the Germans cost 3,598 Canadian lives.

In honour of the occasion here’s something a little different. The following pictures depict a very odd type of hearing aid that first appeared on the battlefields of World War 1.

An important new study reveals a tantalizing new clue about hearing loss.

Iron deficiency anemia (IDA) has been linked to hearing loss in a major study conducted by researchers at Penn State’s Milton S. Hershey Medical Center.

They studied over 300,000 people, ranging from the young to the elderly. Among the findings, the risk of sensorineural hearing loss was 82% higher among those with low iron levels in their blood.

Your bone marrow needs iron to produce hemoglobin for the red blood cells that carry oxygen throughout the body. Iron deficiency can cause symptoms ranging from fatigue to muscle weakness and maybe, just maybe, play a role in hearing loss.

But the study’s lead author, Kathleen P. Schieffer, emphasizes that, “Our study does not say that iron deficiency causes hearing loss, but only that there is a link between the two.”

She also does not recommend that anyone take iron supplements without first consulting a doctor.

The reason for the link is unknown but one theory is gaining ground. We know from animal studies that iron deficiency reduces the flow of hemoglobin to the cochlea and that the auditory nerve cells need a lot of oxygen.

The report concludes that “further research is needed to better understand the potential links between IDA and hearing loss and whether screening and treatment of IDA in adults could have clinical implications in patients with hearing loss”.

The key to restoring lost hearing is finding a way to re-grow hair cells in the cochlea. We’re born with about 30,000 of these tiny sound detectors and because of exposure to noise, age and some types of antibiotics they die off.

The good news: researchers around the world are working to develop techniques to regenerate hairs cells. Now comes word that a team at MIT, Brigham and Women’s Hospital, and Massachusetts Eye and Ear have discovered a combination of drugs that does just that. At least it works in mice.

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Welcome

We are all going deaf, some of us at a faster rate than others. That includes me.
I'm not sure whether to blame The Ramones or some rogue DNA . Whatever. At 40 my hearing tested normal, at 50 I got hearing aids. This site is designed for people like me. I keep up with all the latest technology and medical research. If you are like me and want to improve your hearing and your life, join me. Share your experiences, information and any news you come across. Let's help each other. Digby Cook